published_or_final_version / Education / Doctoral / Doctor of Education

Šiandieninis veiklos pasaulis išgyvena sparčius, visa apimančius ir principinius pokyčius, kur individo veiklos sėkmė priklauso nuo daugelio veiksnių - gebėjimo bendrauti, bendradarbiauti, palaikyti santykius ir komunikuoti su įvairaus amžiaus, išsilavinimo ir pan. individais. Pastarajame kontekste, analizuojant ikimokyklinio ugdymo įstaigos veiklos principus ir tobulinimo galimybes, itin aktualizuojami efektyvaus bendravimo ir bendradarbiavimo procesai, nes tik bendros šeimos ir ugdymo institucijos pastangos, įgalina harmoningą vaiko, kaip socialiai visavertės asmenybės, ugdymą. Pastebėtina ir tai, kad daugelio mokslininkų (Dapkienė, 2002; Juodaitytė, 2002; Schiller, Byrant, 2004; Seliokienė, 2004; Kontautienė, 2006 ir kt.) darbuose, šiuolaikinė ikimokyklinio ugdymo įstaiga traktuojama kaip lygiavertė šeimos partnerė, akcentuojant šeimos ir ugdytojų sąveiką, jų interesų derinimą bei požiūrių į vaiko ugdymą vienovę. Įvertinant tai, šiame baigiamajame darbe, pagrindinis dėmesys yra skiriamas efektyvaus bendradarbiavimo su tėvais sistemos modeliavimui ikimokyklinio ugdymo įstaigoje. Tyrimo objektas - tėvų ir ikimokyklinės įstaigos bendradarbiavimas. Tyrimo dalykas - efektyvaus bendradarbiavimo su tėvais sistemos modeliavimas ikimokyklinio ugdymo įstaigoje. Tyrimo tikslas - išnagrinėti ir empiriškai įvertinti efektyvaus bendradarbiavimo sistemos su tėvais modeliavimo galimybes ikimokyklinėje įstaigoje. Darbo tikslas yra detalizuojamas uždaviniais, lėmusiais tokią darbo... [toliau žr. visą tekstą] / Modern active world is subject to fast, all-inclusive and principal changes and the individual activity success is dependant on numerous factors like communication skills, cooperation, maintenance of relations and interaction with individuals of various age, education, etc. When analysing the activity principles of a preschool education institution and its activity improvement possibilities against the background of above context it is evident that the processes of efficient communication and cooperation are the topical ones as only joint family and educational institution efforts enable harmonious development of a child as a socially full-fledged personality. It should be noted that in the works of most researchers (Dapkienė, 2002; Juodaitytė, 2002; Schiller, Byrant, 2004; Seliokienė, 2004; Kontautienė, 2006; and others) a modern preschool education institution is treated as an equal partner to family thus emphasising the interaction of family and educators, harmonisation of their interests and approaches leading to unity in child education. In view of the above the main attention in this paper has been focused on development of an efficient model of teacher-parents cooperation system at a preschool educational institution. Object of the study – parents-educational institution cooperation. Subject of the study - development of an efficient teacher-parents cooperation system model at a preschool educational institution. Goal of the study is to analyse and empirically evaluate... [to full text]

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The aim of this work was to develop an envelope function method to calculate the electronic states and optical properties of complex quantum well heterostructures, and to demonstrate its effectiveness by application to some device structures of topical interest. In particular, structures have been considered which might form the basis of intensity modulators and polarization insensitive amplifier devices for light at a wavelength of 1.55 µm. The modulator structures considered all have the general form of two coupled quantum wells of different widths as the active region. The application of an electric field in the growth direction is intended to result in a shift in the energy and spatial localisation of the confined states and produce an increase in the absorption coefficient at longer wavelengths than the zero field absorption edge. The effectiveness of certain structures is examined in terms of field induced absorption increase at 1.55 µm. A system which shows a significant increase in absorption coefficient at this wavelength on application of a practical electric field has been identified as a possible candidate for an intensity modulator. In the case of the amplifier, the active region of the most promising structure considered consists of a stepped well which comprises two layers, one with tensile and one with compressive strain. It is known that the presence of the two oppositely strained layers can result in the TE and TM gain peaks appearing at similar photon energies. Our calculations show that a suitable choice of strain and layer widths can result in a small or zero difference between the TE and TM gains at 1.55 µm, which can be important for the polarization insensitive operation of devices in optical communications applications. In order to predict the optical properties of quantum well devices it is necessary to calculate the electron and hole states for a range of in-plane wavevectors. The calculations developed and carried out in this work are based on a multi-layer (eight band) k.p model including strain effects. The interfacial boundary conditions which result from approximations to Burt's exact envelope function theory are included in the model. The effect of an electric field is modelled by including a potential energy term in each layer Hamiltonian which is equal to the average energy shift across the layer in question due to the presence of the field. The model has been developed with flexibility in mind and has applications beyond the specific devices considered in this thesis.

Soil liquefaction has caused major damage to pile foundations in many previous earthquakes. Pile foundations are relatively vulnerable to lateral loads such as those from earthquake shaking; during liquefaction this vulnerability is particularly pronounced due to a loss of strength and stiffness in the liquefied soil. In this research seismic assessment methods for piles in liquefied soil are studied; a simplified approach and a detailed dynamic analysis are applied to a case study of a bridge founded on pile foundations in liquefiable soils. The likely effects of liquefaction, lateral spreading and soil-structure interaction on the bridge during a predicted future earthquake are examined. In the simplified approach, a pseudo-static beam-spring method is used; this analysis can be performed using common site investigation data such as SPT blow count, yet it captures the basic mechanism of pile behaviour. However, the phenomenon of soil liquefaction is complex and predictions of the seismic response are subject to a high level of aleatoric uncertainty. Therefore in the simplified analysis the key input parameters are varied parametrically to identify key features of the response. The effects of varying key parameters are evaluated and summarised to provide guidance to designers on the choice of these parameters. The advanced analysis was based on the effective stress principle and used an advanced constitutive model for soil based on a state concept interpretation of sand behaviour. The analysis results give detailed information on the free field ground response, soil-structure interaction and pile performance. The modelling technique is described in detail to provide guidance on the practical application of the effective stress methodology and to illustrate its advantages and disadvantages when compared to simplified analysis. Finally, a two-layer finite element modelling technique was developed to overcome the limitations conventional two-dimensional (2-D) models have when modelling three-dimensional (3-D) effects. The technique, where two 2-D finite element meshes are overlapped and linked by appropriate boundary conditions, was successful in modelling 3-D characteristics of both deep-soil-mixing walls for liquefaction remediation and pile groups in laterally spreading soil. In both cases the new two-layer model was able to model features of the response that conventional one-layer models cannot; for cases where such aspects are important to the overall response of the foundation, this method is an alternative to the exhaustive demands of full 3-D analysis.

Nanoporous metal films have many applications in a great variety of scientific fields, and especially nanoporous gold films have many applica- tions in green nanotechnology. Hence, structural and optical properties of such materials were investigated. Local density functions and local per- colation functions were calculated by using scaning electron micrographs and the optical properties of the films were calculated using the Hilfer equation. The results are presented in the report as graphs and show how the materials optical properties depend on the structure of the gold films.

Problem: How can segments on Aktietorget explain how a lemon market can not only survive but grow? Purpose: The purpose is to try to explain how Aktietorget can grow under lemon market conditions by gauging investor groupings investment tendencies. Method: Quantitative archival study regarding returns and price per share depending on investor identity. Conclusion: Finance industry investor yields higher returns, which implicates the possibility of rational investing. This is attributed to either identity inherited capabilities or them being agents in the place of the principal. The private investor on the other hand is full principals and has a tendency towards low price per share. All other capital on Aktietorget conforms to the lottery characteristics of Aktietorget.

A recent study of the positronium atom showed that the energy levels could be determined numerically using an effective field theory just as easily as the underlying true theory. Here, we expand on this idea by modeling the three-body positronium-ion and four-body di-positronium molecule with low-energy effective field theories. We then compare the results obtained using the effective theories to those found in a similar manner with the true theory to determine if numerical calculations will converge more quickly using the effective field theory due to removal of the Coulomb divergence. Finally, with the necessary framework in place, we calculate a matrix element needed to evaluate the correction to the magnetic moment of the positronium-ion due to the interaction between the positron and the two electrons which form a spin singlet.

This dissertation covers two different but related topics: the construction of consistent models in type IIB and heterotic string theories, and the higher derivative couplings for D-brane action, which will enable us to relate some models of type IIB to the heterotic side through duality chain. In the first part, we describe an alternative to the KKLT scenario, in which one can achieve de-Sitter space after fixing all moduli. We fix complex structure moduli and the axio-dilaton by deriving the stability conditions for the critical points of the no-scale scalar potential that governs the dynamics of the complex structure moduli and the axio-dilaton in compactifications of type IIB string theory on Calabi-Yau three-folds. In the second part, we show the existence of a class of flux backgrounds in heterotic string theory. The background metric we will consider is a T2 fibration over a K3 base times four-dimensional Minkowski space. Unbroken space-time supersymmetry determines all background fields except one scalar function which is related to the dilaton. The heterotic Bianchi identity gives the same differential equation for the dilaton, and we will discuss in detail the solvability of this equation for backgrounds preserving an N=2 supersymmetry. In the third part, we obtain the higher derivative D-brane action by using both linearized T-duality and string disc amplitude computation. We evaluate disc amplitude of one R-R field C^(p-3) and two NS-NS fields in the presence of a single Dp-brane in type II string theory. We obtain the action for the higher derivative brane interactions among one R-R field C^(p-3) and two NS-NS B-fields after carefully comparing the supergravity amplitudes with the corresponding string amplitude up to alpha^r2 order. We also show that these higher derivative brane couplings are invariant under both R-R and NS-NS B-field gauge transformations, and compatible with linear T-duality.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.